[Coin-discuss] LP and TM solutions (Heesu Hwang)

[Francois Margot]

Heesu:

Try to run valgrind on your code. My guess is that memory access errors
occur somewhere (likely in your own code). Generating heuristic solutions
properly with Bcp is a little bit tricky. There is an example in 
the BAC code available in COIN/Examples/BAC.

Negative variable numbers may exist internally in Bcp, but they should
not appear in the output. Variable 1481 in a problem with 80 variables
is impossible if no column generation is done.

Francois

On Sun, 4 Sep 2005 coin-discuss-request at list.coin-or.org wrote:

> Date: Sat, 3 Sep 2005 12:59:23 -0500
> From: "Heesu Hwang" <hxh9528 at omega.uta.edu>
> Subject: [Coin-discuss] LP and TM solutions
> To: "'Discussions about open source software for Operations Research'"
> 	<coin-discuss at list.coin-or.org>
> Message-ID: <000001c5b0b1$37dc4690$020ba8c0 at Peter>
> Content-Type: text/plain;	charset="us-ascii"
>
> Hello,
>
> Following output is the result of a LP relaxed problem.
> Notice that it is a binary solution and that I am using Default
> test_binary() to check the feasibility.
> LP packs the feasible solution, and TM unpacks it.
> However the solution that TM displays is different from what LP packed.
>
> 1) Anybody has an idea what is going on in here?
>
> 2) Do negative internal indices of Algo var make any trouble?
>
>
> Thanks,
>
> Heesu Hwang.
>
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> LP: *** Starting iteration 11 ***
>
> LP:   Matrix size: 80 vars x 31 cuts
> LP:   Solution value: -1002851.9760 / 2 , 4
> LP: Default display_lp_solution() executed.
>  LP : Displaying LP solution (RelaxedSolution) :
> LP: Default display_lp_solution() executed.
>   LP : Displaying solution :
>  Algo  var (internal index:      5                    ) at 1.0000
>  Algo  var (internal index:     16                    ) at 1.0000
>  Algo  var (internal index:     33                    ) at 1.0000
>  Algo  var (internal index:     45                    ) at 1.0000
>  Algo  var (internal index:     48                    ) at 1.0000
>  Algo  var (internal index:     49                    ) at 1.0000
>  Algo  var (internal index:     50                    ) at 1.0000
>  Algo  var (internal index:     51                    ) at 1.0000
>  Algo  var (internal index:     57                    ) at 1.0000
>  Algo  var (internal index:    152                    ) at 1.0000
>  Algo  var (internal index:   1431                    ) at 1.0000
>  Algo  var (internal index:  -7060                    ) at 1.0000
>
> LP: Default test_binary() executed.
> LP: Default pack_feasible_solution() executed.
> TM: Default unpack_feasible_solution() executed.
> TM: Solution found at 516.580 sec.
> TM: Solution value: -959109.456000 (best solution value so far:
> -1061466.200000)
>